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Pycnopodia helianthoides

(Many-Legged Sunflower)

Common Names

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Common Names in English:

Many-Legged Sunflower, Sunflower Star, Twenty-Rayed Star

Description

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Physical Description

Species Pycnopodia helianthoides

This is the largest seastar in the Rosario area, with a diameter of up to 90 cm. It has 20 or more rays (but occasionally may be as few as 15), abundant pedecellariae, and many spines projecting from its limp, flaccid tissue (picture). A row of spines along the margins of the rays is longer than the other spines. Nearly always orange or pinkish; sometimes purplish, yellowish, or brown; with white spines.

Habitat

Mostly subtidal , rocky, gravelly, or sandy bottoms . Depth Range : Low intertidal to 435 m. Nearly always subtidal.

Typically found in the intertidal zone at the water's edge at a mean distance from sea level of 77 meters (251 feet).Standard Deviation = 330.540 based on 172 observations. Terrestrial altitude and ocean depth information for each observation from British Oceanographic Data Centre.

Biology

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Diet

This species is a voracious subtidal predator , feeding on bivalves , snails, chitons , urchins, other asteroids, sea cucumbers, sand dollars, and crabs (in other words, just about anything it wants!). It will also scavenge dead animals. In Puget Sound this species excavates butter clams (Saxidomus gigantea) by picking up sediment particles over the clam, passing them out to the ends of the rays , and dropping them. Often eat urchins such as Strongylocentrotus purpuratus, whose spines may pierce through from the stomach to the aboral surface. Can evert its stomach but more often swallows its prey whole.

Reproduction

Spawns March to July (some also in winter); has fertilizable eggs at least from December to June. May stand on the tips of their rays while spawning. Pelagic larvae metamorphose to benthic , 5-rayed juveniles at 9-10 weeks.

Behavior

This seastar can move extremely rapidly for a seastar. Its presence elicits an escape reaction from many species such as the spiny scallop Chlamys hastata, the sea cucumber Parastichopus californicus, and limpets. may be the largest and fastest seastar in the world. It can move up to 3 meters per minute, and has been known to travel at least 3 km . It has over 15,000 tube feet. Tiny, newly metamorphosed juveniles of this species have only 5 rays but rays are added as the individual grows. Has very prominent spines and (crossed) pedicellulariae, plus purple papulae. Loss of rays upon handling seems to be due to autotomy . Predators include Alaska King crab and some large Cancer crabs. Individuals are agressive toward one another (and to almost any other seastar).

Taxonomy

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Notes

Name Status: Accepted Name . Latest taxonomic scrutiny: 27-Dec-2004

Similar Species

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This seastar is larger and has more rays than any other seastar in our area. Small individuals could be confused with Solaster dawsoni or Crossaster papposus, but both of those species have 16 or less rays, no pedicullariae, and are not as markedly limp as Pycnopodia is.. S. dawsoni also does not have the promenent projecting spines, and C. papposus' spines are not extra prominent along the margins of the rays as they are in this species.

Members of the genus Pycnopodia

There are approximately 3 species in this genus:

P. helianthiodes · P. helianthoides (Many-Legged Sunflower) · P. heliathoides

Bibliography

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More Info

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal February 01, 2008:

Identifiers

Footnotes

Last Revised: 2008-11-03